Non-cotton swab sample collection may not affect salivary melatonin assay results

Abstract Background Salivary melatonin levels have been analyzed in many research fields, including physiological anthropology. Although various devices have been utilized for saliva collection, cotton swabs are among the most common. However, previous studies have reported that cotton swabs may int...

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Main Authors: Tomoaki Kozaki, Yuki Hidaka
Format: Article
Language:English
Published: BMC 2018-06-01
Series:Journal of Physiological Anthropology
Subjects:
Online Access:http://link.springer.com/article/10.1186/s40101-018-0178-6
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author Tomoaki Kozaki
Yuki Hidaka
author_facet Tomoaki Kozaki
Yuki Hidaka
author_sort Tomoaki Kozaki
collection DOAJ
description Abstract Background Salivary melatonin levels have been analyzed in many research fields, including physiological anthropology. Although various devices have been utilized for saliva collection, cotton swabs are among the most common. However, previous studies have reported that cotton swabs may interfere with melatonin assay results, whereas synthetic swabs may not. These studies compared only mean melatonin levels between passive and synthetic-polymer swab collection methods but did not evaluate relative and proportional biases. Our study examines the effects of using swabs made of materials other than cotton, such as polypropylene–polyethylene polymer, on salivary melatonin assay results using a Bland–Altman (BA) plot. The effects of the saliva collection method were analyzed using two concentrations of melatonin, lower (< 6 pg/ml) and higher (> 6 pg/ml), because the threshold of dim light melatonin onset was lower than 6 pg/ml in many studies. Results Differences detected between passive and polypropylene–polyethylene polymer swab methods of saliva collection were not significant in both lower (< 6 pg/ml) and higher (> 6 pg/ml) melatonin levels detected. All correlations between the collection methods were significant, and 95% confidence intervals for differences in melatonin levels in all samples detected using passive and non-cotton swab saliva collection methods included zero in the BA plots. Averages and differences between non-cotton and passive saliva collection obtained from the BA plots were not significantly correlated at lower and higher melatonin levels. Conclusions Our findings demonstrate that swabbing methods, including the use of polypropylene–polyethylene polymer, do not affect salivary melatonin assay results. Therefore, the authors suggest that polypropylene–polyethylene polymer swab methods are appropriate for the assessment of dim light melatonin onset and dose response of the circadian system to light.
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spelling doaj.art-3a5bc9bc759549348ae80733f9a6ea762022-12-21T22:14:17ZengBMCJournal of Physiological Anthropology1880-68052018-06-013711510.1186/s40101-018-0178-6Non-cotton swab sample collection may not affect salivary melatonin assay resultsTomoaki Kozaki0Yuki Hidaka1Fukuoka Women’s UniversityKyushu UniversityAbstract Background Salivary melatonin levels have been analyzed in many research fields, including physiological anthropology. Although various devices have been utilized for saliva collection, cotton swabs are among the most common. However, previous studies have reported that cotton swabs may interfere with melatonin assay results, whereas synthetic swabs may not. These studies compared only mean melatonin levels between passive and synthetic-polymer swab collection methods but did not evaluate relative and proportional biases. Our study examines the effects of using swabs made of materials other than cotton, such as polypropylene–polyethylene polymer, on salivary melatonin assay results using a Bland–Altman (BA) plot. The effects of the saliva collection method were analyzed using two concentrations of melatonin, lower (< 6 pg/ml) and higher (> 6 pg/ml), because the threshold of dim light melatonin onset was lower than 6 pg/ml in many studies. Results Differences detected between passive and polypropylene–polyethylene polymer swab methods of saliva collection were not significant in both lower (< 6 pg/ml) and higher (> 6 pg/ml) melatonin levels detected. All correlations between the collection methods were significant, and 95% confidence intervals for differences in melatonin levels in all samples detected using passive and non-cotton swab saliva collection methods included zero in the BA plots. Averages and differences between non-cotton and passive saliva collection obtained from the BA plots were not significantly correlated at lower and higher melatonin levels. Conclusions Our findings demonstrate that swabbing methods, including the use of polypropylene–polyethylene polymer, do not affect salivary melatonin assay results. Therefore, the authors suggest that polypropylene–polyethylene polymer swab methods are appropriate for the assessment of dim light melatonin onset and dose response of the circadian system to light.http://link.springer.com/article/10.1186/s40101-018-0178-6Saliva sampleMelatoninNon-cotton swab
spellingShingle Tomoaki Kozaki
Yuki Hidaka
Non-cotton swab sample collection may not affect salivary melatonin assay results
Journal of Physiological Anthropology
Saliva sample
Melatonin
Non-cotton swab
title Non-cotton swab sample collection may not affect salivary melatonin assay results
title_full Non-cotton swab sample collection may not affect salivary melatonin assay results
title_fullStr Non-cotton swab sample collection may not affect salivary melatonin assay results
title_full_unstemmed Non-cotton swab sample collection may not affect salivary melatonin assay results
title_short Non-cotton swab sample collection may not affect salivary melatonin assay results
title_sort non cotton swab sample collection may not affect salivary melatonin assay results
topic Saliva sample
Melatonin
Non-cotton swab
url http://link.springer.com/article/10.1186/s40101-018-0178-6
work_keys_str_mv AT tomoakikozaki noncottonswabsamplecollectionmaynotaffectsalivarymelatoninassayresults
AT yukihidaka noncottonswabsamplecollectionmaynotaffectsalivarymelatoninassayresults